Tribological properties and studies in SBF of Ta2O5/TiN/TiO2 monolayer and bilayer coatings on biomedical Ti6Al4V alloy

Melis Yurddaskal,Hülya Durmuş 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.5

In this study, Ta 2 O 5 , TiN, and TiO 2 are coated with magnetron sputtering method as monolayer and bilayer on Ti6Al4V alloy used in biomedical applications. The deposited coatings are characterized, and their mechanical properties are determined by nanoindentation tests. As a result of the pin-on disc wear test performed in dry environment and room temperature, in vitro corrosion test was applied to the samples with high wear resistance, and the information about the tribological properties was obtained. Experimental results show that the existence of the intermediate layer has also significant effect on the corrosion resistance of the coatings. The biocompatibility of the Ta 2 O 5 /TiO 2 coating was examined by keeping it in simulated body fluid (SBF) due to its noticeable wear and corrosion resistance properties, the growth of apatite, which is described as an indicator of biocompatibility, occurred on the sample surface after 7 day.

Differences in Pain Characteristics and Functional Associations between Nursing Home Residents and Community-Dwelling Older Adults: A Cross-Sectional Study

Melis Tansuğ,Turhan Kahraman,Arzu Genç 대한노인병학회 2021 Annals of geriatric medicine and research Vol.25 No.3

Background: Pain is one of the most critical issues in older adults, and the place of residence may play an important role in pain characteristics and related factors. However, it is an understudied subject. This study investigated differences in pain characteristics and functional associations between nursing home residents and community-dwelling older adults. Methods: Older adult participants were recruited from nursing homes (n=73) and the community (n=73). Pain characteristics, including type, intensity, and number of pain sites, were evaluated. Other outcome measures were functional mobility, walking speed, functional independence, physical activity, anxiety, depression, and health-related quality of life. Results: Nursing home residents experienced musculoskeletal pain more frequently and had a greater number of pain sites than community-dwelling older adults (p<0.05). Walking speed and mobility were significantly lower and anxiety and depression were significantly higher in nursing home residents (p<0.05). While higher pain intensity was significantly correlated with low scores on physical measures, low health-related quality of life, and higher depression and anxiety symptoms in both groups (p<0.05), the magnitudes of the correlations were much higher in nursing home residents. The number of pain sites was significantly correlated with low scores on physical measures, low health-related quality of life, and higher depression and anxiety symptoms mainly in nursing home residents (p<0.05). Conclusion: Compared to community-dwelling older adults, nursing home residents experienced musculoskeletal pain more frequently and at more sites in the body. Higher pain intensity and number of pain sites were associated with worse clinical variables, mainly in nursing home residents. This study highlights the importance of regular pain assessment, especially in nursing home care settings.

The effect of curvature on the impact response of foam-based sandwich composite panels

Melis Yurddaskal,Buket Okutan Baba 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.20 No.5

The aim of this study is to investigate the impact behavior and impact-induced damage of sandwich composites made of E-glass/epoxy face sheets and PVC foam. The studies were carried out on square flat and curved sandwich panels with two different radius of curvatures. Impact tests were performed under impact energies of 10 J, 25 J and 80 J using an instrumented drop-weight machine. Contact force and displacement versus time and contact force- displacement graphs of sandwich panels were presented to determine the panel response. Through these graphs, the energy absorbing capacity of the sandwich panels was determined. The impact responses and failure modes of flat and curved sandwich panels were compared and the effect of curvature on sandwich composite panel was demonstrated. Testing has shown that the maximum contact force decrease while displacement increases with increasing of panel curvature and curved panels exhibits mixed failure mode, with cylindrical and cone cracking.

Association of Adipokines, Insulin Resistance, Hypertension and Dyslipidemia in Patients with Psoriasis Vulgaris

( Melis Coban ),( Levent Tasli ),( Sebahat Turgut ),( Seyma Ozkan ),( Melek Tunc Ata1 ),( Fulya Akın ) 대한피부과학회 2016 Annals of Dermatology Vol.28 No.1

Background: Systemic inflammation in psoriasis causes insulin resistance and cardiovascular diseases. Adipokines are adipose-tissue-derived factors that are involved in metabolic processes. It is thought that these adipokines are associated with the development of psoriasis. Objective: The purpose of this study was to determine the changes in adipokine levels, insulin resistance, hypertension, and dyslipidemia over a 12-week period. Methods: The study comprised 35 psoriasis patients and 50 controls. Blood samples were obtained twice from the patients, one sample at the start and one at the end of a 12-week follow-up period. The following parameters were assessed in both groups: serum fasting glucose, fasting insulin, homeostasis model assessment-estimated insulin resistance (HOMA-IR) index, serum lipids, adiponectin, leptin, resistin, chemerin, omentin, vaspin, visfatin, retinol-binding protein 4, and high-sensitivity C-reactive protein (hs-CRP) levels; blood pressure; body mass index; and the psoriasis area severity index (PASI) scores. Results: The patients showed an improvement in the PASI score and a significant decrease in serum hs-CRP, omentin, and chemerin values. Moreover, at the start of the follow-up, the psoriasis patients had significantly lower levels of adiponectin and visfatin and significantly higher levels of vaspin and resistin than those of the control group. Visfatin levels correlated negatively with low-density lipoprotein (LDL) and cholesterol, while vaspin and omentin levels correlated positively with diastolic blood pressure. Decreased adiponectin levels correlated negatively with diastolic blood pressure and LDL. Conclusion: Plasma levels of adipokines might be useful for evaluating the disease activity of psoriasis and its comorbidities.

Production and properties of tooth-colored yttria stabilized zirconia ceramics for dental applications

Kaplan, Melis,Park, Jongee,Young Kim, Soo,Ozturk, Abdullah Elsevier 2018 Ceramics international Vol.44 No.2

<P><B>Abstract</B></P> <P>Dense zirconia stabilized with 3mol% yttria ceramics were produced in disc shape by first cold isostatically pressing at 100MPa and then sintering at 1450°C at ambient laboratory conditions. Coloring was accomplished by immersion the discs in NiCl<SUB>2</SUB>, MoCl<SUB>3</SUB>, and NiCl<SUB>2</SUB> + MoCl<SUB>3</SUB> solutions for 5, 30, and 60s. Different concentrations (0.1, 0.25, and 0.5wt%) were applied to get the color of natural tooth. The density, color, microhardness, fracture toughness, compressive strength, and wear rate of the discs were measured to evaluate the suitability of the colored discs for dental applications. Color assessments were made by measuring CIE Lab <I>L</I> <SUP> <I>*</I> </SUP>, <I>a</I> <SUP> <I>*</I> </SUP>, <I>b</I> <SUP> <I>*</I> </SUP>, and Δ<I>E</I> <SUP> <I>*</I> </SUP> values. Low temperature degradation of the samples was evaluated by aging sensitivity tests in autoclave for 2, 4, and 6h. Results have shown that color produced depends on the kind and concentration of the colorant solution while time of immersion has no significant effect on coloring process. Coloring solutions containing 0.1 and 0.25wt% MoCl<SUB>3</SUB> provided clinically acceptable color with the ΔE* value ranging from 5.16 to 6.42 for dental applications.</P>

Hazardous Health Behaviour among Medical Students: a Study from Turkey

Nacar, Melis,Cetinkaya, Fevziye,Baykan, Zeynep,Yilmazel, Gulay,Elmali, Ferhan Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.17

Background: Hazardous health behaviour in young people is an important factor that affects the individual risk for non-communicable diseases and other disorders later in life. This study aimed to determine the hazardous health behaviour of first and last class medical students of Erciyes University. Materials and Methods: This descriptive study was carried out with 240 medical students from the first and 130 students from the last (sixth) class. Data were obtained by questionnaire between March-April 2012. In total, 339 students were included with a response rate of 91.6%. Socio-demographic characteristics, school success, self-reported economic difficulties, health perceptions, hazardous health behaviour related to chronic disease, tobacco, alcohol, substance use, body weight, height, traffic, violence and nutrition were assessed in line with the literature. Results: Of the participants; 64.0% were from first and 36.0% were from the last class. Mean ages for the first and last classes were $19.4{\pm}1.5$ and $24.0{\pm}1.5years$, respectively. In the current study, males exhibited more hazardous behaviour than females. Sime 19.8% of the students in the study group used alcohol, 35.4% used a waterpipe, and 24.8% used tobacco at least once. These rates increased in both genders in the last class and the increase in males was significant. Some 3.8% of the students in the current study used pleasure-inducing illegal substances at least once. All the students participating in the current study were single, the number of males reported not using condoms (8.6%) was 4.56 times higher compared to females. Some 64.0% of the students did not perform physical activity lasting at least 30 minutes for five times a week, 13.0% did not sleep for mean 7-8 hours daily, males having a 2.9 times higher risk. More than 1/3 of the students did not consume cooked vegetable dishes and 1/4 did not consume fresh fruits and salads, the rates were higher among males. Conclusions: In the current study, hazardous health behaviour was prevalent among medical students, with higher risks among males and last class students. According to these results, medical curriculum may be focused on decreasing hazardous health behaviour. In addition, in order to prevent unhealthy behaviour, the number of youth-friendly health facilities should be increased.

Exploring Existential Authenticity in Sardinian Mamuthones and Issohadores Carnival

Claudia Melis,Ernestina Giudici 한국문화관광학회 2021 문화관광연구 Vol.23 No.2

Given the centrality of the concept of authenticity in cultural tourism studies, the purpose of this research is to frame the case study of the Mamuthones and Issohadores carnival within this debate. Authenticity has been largely discussed by scholars from a broad range of perspectives. In particular, the basis for our work will be the concept of existential authenticity. While previous studies suggest that tourism can offer escape from everyday inauthentic life, earliest contributions show how tourism can foster the adoption of an authentic life beyond the trip. Whatever the meaning is, this festival attracts every year a number of visitors. Our question is why are tourists attracted by this kind of event? With this in mind we will try to understand whether and how the concept of existential authenticity is related to the Mamuthones and Issohadores carnival, trying to identify what the attributes could be that lead us thinking that experiencing this event could convey to tourists the feelings associated to existential authenticity. This constitutes the first step of a broader study who aims to explore, through a phenomenological approach, the experience of tourists of this event and to compare it with similar carnivals in the Mediterranean and elsewhere.

Health Promoting Lifestyle Behaviour in Medical Students: a Multicentre Study from Turkey

Nacar, Melis,Baykan, Zeynep,Cetinkaya, Fevziye,Arslantas, Didem,Ozer, Ali,Coskun, Ozlem,Bati, Hilal,Karaoglu, Nazan,Elmali, Ferhan,Yilmaze, Gulay Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.20

Background: The aim of this study was to determine the predictors of health promoting lifestyle behaviour among medical students attending seven of the medical schools in Turkey. Materials and Methods: This crosssectional descriptive study was performed during the second semester of the first and last (sixth) years of study from March to May 2011. A questionnaire with two sections was specifically designed. The first section contained questions on demographic characteristics; the second consisted of the Health Promoting Lifestyle Profile II (HPLP) Scale. From a total of 2,309 medical students, 2,118 (response rate 91.7%) completed the questionnaire. Data were analyzed using descriptive statistics, t, Anova, Tukey test and binary logistic regression analysis. The research was approved by the Ethics Committee of Erciyes University. Results: The mean age was $20.7{\pm}2.9$ years and it was found that 55.1% were men, 62.3% were in the first year. The overall prevalence of smoking was 19.1%, and for drinking alcohol was 19.4%. HPLP point averages of the first year students were $129.2{\pm}17.7$, and for last year $125.5{\pm}19.0$. The overall mean score for the HPLP II was $2.5{\pm}0.4$. They scored highest on the spiritual growth subscale ($2.9{\pm}0.5$), interpersonal relations ($2.8{\pm}0.5$), health responsibility subscale ($2.3{\pm}0.5$), nutrition subscale ($2.3{\pm}0.5$), stress management subscale ($2.3{\pm}0.4$), and the lowest subscale physical activity ($2.0{\pm}0.5$). It is established that student's grade, educational level of parents, economic status of family, marital status, smoking and general health perception of the students resulted in a significant difference in HPLP Scale total score average and the mean score of majority of subscales. There was no statistically significant difference between the total HPLP when evaluated for gender, chronic disease, alcohol drinking status and BMI. Conclusions: Based on these results, particularly in the curriculum of medical students in order to increase positive health behaviours including physical activity, health promotion issues, and giving more space to aim at behaviour change in these matters is recommended.

Metaplastic Breast Carcinoma: a Heterogeneous Disease

Gultekin, Melis,Eren, Gulnihan,Babacan, Taner,Yildiz, Ferah,Altundag, Kadri,Guler, Nilufer,Ozisik, Yavuz,Yazici, Gozde,Hurmuz, Pervin,Gurkaynak, Murat Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.6

The aim of this study is to evaluate clinicopathologic characteristics and the multi-disciplinary treatment results of metaplastic breast cancer (MBC) patients treated in a single institute. Seventeen female patients with MBC treated in our department between June 2000 and January 2012 were identified and retrospectively evaluated. The median age at diagnosis was 46 years (range, 26-66 years). The median tumor size at diagnosis was 3.5 cm (range 1.5-12 cm). Six (35%) patients underwent breast conservation surgery and 11 (65%) mastectomy. Axillary lymph node metastasis was found in 6 (35%) patients. Twelve (71%) had triple negative tumors. Postoperative RT and systemic adjuvant treatment was given to all patients accordingly to stage and biological characteristics. Median follow-up time was 27 months (range, 12-151 months). At the time of this analysis, 14 (82%) patients were alive with no evidence of disease, and 1 (6%) was alive with disease. The 3-year OS was 91% and 5-year 80%, and DFS rates were 76% and 76%, respectively. Despite the young age of our patients with mostly high grade tumors, larger tumor size and higher rates of lymph node metastasis, the survival outcomes in our study are favorable in comparison with previously reported series.

Towards Full Thickness Small Intestinal Models: Incorporation of Stromal Cells

Asal Melis,Rep Mila,Bontkes Hetty J.,van Vliet Sandra J.,Mebius Reina E.,Gibbs Susan 한국조직공학과 재생의학회 2024 조직공학과 재생의학 Vol.21 No.3

Introduction Since small intestine is one of the major barriers of the human body, there is a need to develop reliable in vitro human small intestinal models. These models should incorporate both the epithelial and lamina propria compartments and have similar barrier properties compared to that of the human tissue. These properties are essential for various applications, such as studying cell–cell interaction, intestinal diseases and testing permeability and metabolism of drugs and other compounds. The small intestinal lamina propria contains multiple stromal cell populations with several important functions, such as secretion of extracellular matrix proteins and soluble mediators. In addition, stromal cells influence the intestinal epithelial barrier, support the intestinal stem cell niche and interact with immune cells. Methods In this review, we provide an extensive overview on the different types of lamina propria stromal cells found in small intestine and describe a combination of molecular markers that can be used to distinguish each different stromal cell type. We focus on studies that incorporated stromal cells into human representative small intestine models cultured on transwells. Results and Conclusion These models display enhanced epithelial morphology, increased cell proliferation and human-like barrier properties, such as low transepithelial electrical resistance (TEER) and intermediate permeability, thus better mimicking the native human small intestine than models only consisting of an epithelium which generally show high TEER and low permeability.